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why only 1 SAS Disk displayed of 6 disks

 
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Mohammad Iqbal_1
Occasional Advisor

why only 1 SAS Disk displayed of 6 disks

I have new rx2660 with six SAS disks. But when I run command '# ioconfig -fC' there's only ONE disk displayed,with the description "Logical Volume". My OS is HP-UX 11.23. Please help me to resolve this problem so I can view all the 6 SAS disk. Thx
Iqbal "the Captain"
10 REPLIES
Steven E. Protter
Exalted Contributor
Solution

Re: why only 1 SAS Disk displayed of 6 disks

Shalom,

The rx2660 server has a hardware raid card.

This permits the hardware to present the system with one hardware raid configured disk.

You boot into this configuration and can see it with a web server that ships with PSP for HP-UX.

I am almost sure this is not a problem. My guess is you have your six disks configured as a gigantic raid 5 disk.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
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TTr
Honored Contributor

Re: why only 1 SAS Disk displayed of 6 disks

> only ONE disk displayed,with the description "Logical Volume".
How big is this logical volue?

Use the /opt/raidsa/bin/saconfig utility to get detailed information about the raid controller and its disks.
/opt/raidsa/bin/saconfig /dev/sasd0

If your raid controller device is other than sasd0, use that instead. Look at a full ioscan listing for the sas device.

It is possible that you have an upgraded controller with a single huge LUN for all six disks because with the default raid controller on the rx2660, you are limited to one or two mirrored pairs and a host spare. All other SAS disks would be visible to the OS as simple disks.
Mohammad Iqbal_1
Occasional Advisor

Re: why only 1 SAS Disk displayed of 6 disks

Thank you for your replies. Please tell me what should I do if I need to present all the 6 disks by ioscan command. Do I have to remove the raid configuration. Would you please to show me the detail steps required. I'm new with raid configuration. Thank you before.
Iqbal "the Captain"
Steven E. Protter
Exalted Contributor

Re: why only 1 SAS Disk displayed of 6 disks

Shalom,

First lets be sure this is what we are dealing with.

ioscan -fnC disk

See how many disks you see. I think you will see one.

Then to change this, you will have to change the system hardware raid configuration.

This will if its a gigantic raid 5 or raid 10 volume leave you with an unbootable system. You will after changing the RAID configuration have to re-install the OS.

I with six disks would do the following:

1 Raid 1 volume via hardware to be boot disk.

The other 4 disks in a second hardware raid volume. If you plan to host a write intensive database, this I would also do as raid 1. If its less write intensive, the second volume would be raid 5.

Why hardware raid? The raid card has its own CPU and its better to handle the i/o there than with the OS. Better performance, easier disk replacement.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
TTr
Honored Contributor

Re: why only 1 SAS Disk displayed of 6 disks

I do not recommend deleting the raid config and presenting the 6 disks to the server. You should at least keep one mirrored pair for the OS boot disk. Before anything else you need to provide details about the raid configuration using the command given above as well as full ioscan listing (ioscan -fnk).
Mohammad Iqbal_1
Occasional Advisor

Re: why only 1 SAS Disk displayed of 6 disks

Hi Steven, thank you for your explanation.
Yes, you're right. When I run ioscan -fnC disk, I only see one disk, and the description is "logical volume".

I also say thank you to TTr for your explanation. Yes, I manage to keep one mirrored pair for the OS boot disk.

Guys, please write down the detai steps required for this implementation. Many thanks.
Iqbal "the Captain"
TTr
Honored Contributor

Re: why only 1 SAS Disk displayed of 6 disks

You did not provide any of the information we asked, ioscan and saconfig output.
Torsten.
Acclaimed Contributor

Re: why only 1 SAS Disk displayed of 6 disks

You have most likely a P400 smartarray controller installed, so you can only work with logical drives, not individual disks.

Post

# ioscan -fn

to confirm.

Hope this helps!
Regards
Torsten.

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Kranti Mahmud
Honored Contributor

Re: why only 1 SAS Disk displayed of 6 disks

Hi Iqbal,

Check the following thread, it will work for you, if it does, please assign points:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1335662

Rgds-Kranti
Dont look BACK as U will miss something INFRONT!
Mohammad Iqbal_1
Occasional Advisor

Re: why only 1 SAS Disk displayed of 6 disks

Guys, thank you for your help. I did know why there's only one disk displayed, because it's raid 5.
Iqbal "the Captain"